Grip for use in straining and jointing electrical conductors, wires, and the like



July 17, 1934. B. MCMAHON 1,966,989

GRIP FOR USE IN STRAINING AND JOINTING ELECTRICAL CONDUCTORS, WIRES, AND THE LIKE Filed March so, 1932 I II F'atent ed July 17, I934 v g M 1,966,989

GRIP FOR USE IN. STRAINlNGcAh TD JOINT-I ING ELECTRICAL CONDUCTORS, WIRES,

AND THEVLIKE Bernard McMahon; -Kooyong, Victoria, Australia Application March.30 1932,.SerialNo. 602,062 1 4 -5 Claims. ((1254-51) This invention has reference to an improved grip for use in straining and jointing electrical conductors, wires and the like and has as its object means whereby a clear space is provided 5 between the gripping jaws and the pole or like support to which pole the straining mechanism is attached, sufiicient to permit free operation of a pair of jointing clamps; tongs or the likeso as to make a joint without bending the wire on either side of the joint.

Up to the present time the types of wire grip used grip the wire in such a manner that the portion of the wire between the gripping jaws and the pole or like support is in contact with or very close to the metal and strap portions ofthe wire grip, and this close proxmity of the wire and portions of, the wire grip for the whole distance between the gripping jaws and the pole or like support restricts the free use of jointing clamps, tongs or the like and causes the operation of making joints the wire between the gripping jaws and the pole to be slower and more difficult of execution than if a free space were available in which to operate the required tools and to make the joint in the portion of the wire not under tension i. e. between the gripping jaws and the pole.

Now my invention has been devised in order to overcome the foregoing disadvantages and is based upon the appreciation of the advantagesto be attained if a grip for straining wires and the like could be designed and pivotally attached to a connecting arm protruding from the straining mechanism casing in such a manner as to provide a clear space suflicientto permit free operation of the jointing clamps or the like and the making-of a joint without bending'the wire on either side of the joint. It was realized that such a grip would v possess great advantages facilitating the opera 40 tion to be performed on the desired portion of the wire.

The invention is characterized by an offset connecting arm preferably bowed, one end of which is fixedly attached to a casing carrying the strainer operating mechanism so that the continued centre line of the bowed arm preferably passes through the longitudinal centre line of the roller around which the free end of .a leather strap passes, the other end of the bowed arm being provided with a pivotally mounted jaw operating lever suitably and pivotally mounted to the upper and lower gripping jaws which arealso provided with a link pivotally mounted thereon so as to ensure a parallel movement of the upper gripping jaw in relation to the effective surface of the lower gripping jaw which surface is maintained in correct alignment-by a downwardly projecting plate integral with the lower jaw the lower portion of which plate is provided with an opening through-which is free to pass a curved end portion of the bowedarm.

The bowed arm is so positioned below the upper surface of the lower'jaw; which upper surface is in the line or direction of pull and a continuation of the line of the wire'under tension so asto provide a clear space sufficient to permit free operation of the jointing cla'mps'or the like for the making of a joint between the gripping jaws and the strainer operating mechanism oasing. The gripping jaws aremaintained in a normally closed position by the action of a spring which is compressed on the forward movement of the bowed arm and strained operating mechanism; the action ofthismovement causes the jaw operating lever to pivot about the point where it is mounted to the lower jaw thus raising the upper jaw which is maintained in parallel relationship with the lower jaw by the hereinbefore mentioned pivoted link. Simultaneously while this movement is taking place the-casing carrying the strainer operating mechanism moves forward so that the longitudinal centre line of the pin carrying the roller mounted between the sides of the casing continues to remain in a path in line with the upper surface of the lower gripping jaw. This path is the line of direction of pull of the apparatus and is a continuation of the lineor direction of the wire under strain on the side of the gripping jaws opposite the strainer operating mechanism. The strainer operating arrangement is provided with anchoring means preferably of the leather strap and hook type one end of'the strap being anchored to the casing and passing through a suitable shackle on the anchoring hook and back around a roller in front of which is positioned locking meansin order to prevent the strap when desired from slipping back when tension is applied to the said strap for the purpose of straining the Wire held between the gripping jaws.

On pulling the strap the whole arrangement is drawn towards the'anchoring hook which causes the wire between the gripping jaws to be placed in tension at the same time thejaw operating lever is actuated forcingthe upper jaw on to the lower jaw between which jaws the wire is held thus preventing same from slipping when tension is applied as'the more thetension is applied the firmer thewire is gripped between the 'jaws. The tension is maintained by the locking means working in conjunction with the strap and the roller while the required operation is being carried out after which the locking means is released allowing the gripping jaws to open and become free from contact with the wire. The strainer operating arrangement is so constructed that the line of direction of pull passes through the longitudinal centre line of the pin on which the roller carrying the strap rotates. This line of pull is always in line with the upper surface of the lower gripping jaw so that the wire is not at any time subject to any bending stress either on the ends of the jaws or on either side of the joint. 1

An important feature embodied in my invention is the means whereby the strainer operating mechanism casing is connected to the gripping jaws, said means comprising an offset arm preferably bowed and a jaw operating lever said arm and lever being so positioned that the line or direction of pull on the apparatus is a continuation of the line or direction of the wire under strain on the side of the gripping jaws opposite the straining mechanism and anchoring means the said connecting arm being offset so as to provide a clear space sufiicient to permit free operation of a pair of jointing clamps or the like between the gripping jaws and the beforementioned casing.

Another important feature embodied in my invention is the means whereby the wire regardless of its diameter when secured in the gripping jaws is not subjected to any bending either on the ends of the jaws or on either side of the joint when the tension imparting mechanism is anchored to a pole or like support.

A further important feature of my invention is the means whereby the wire is prevented from becoming damaged should the apparatus fall after the wire has been gripped but before the straining has commenced said means comprising smooth and rounded ends of the upper and lower gripping jaws which are free from sharp edges.

A still further important feature embodied in my invention is the means whereby the upper surface of the lower gripping jaw is maintained in constant relationship and in line with the longitudinal centre line of the roller pin mounted to the casing regardless of the position of the upper gripping jaw whether the jaws are fully open or closed.

Now in order that my invention may be more readily understood reference will be made to the accompanying drawing in which:-

Figure 1 is a side elevation of the apparatus in operative position.

Figure 2 is a side elevation of the apparatus Without the anchoring means showing in silhouette the position of the offset arm and jaw operating lever when said jaws are in open position.

Figure 3 is a plan view of Figure 2.

Figure 4 is a side elevation of the gripping means in closed position showing in silhouette the open position of the jaws.

According to my invention I provide a suitab boxlikecasing 1 which is open at the top and bottom and constructed so as to carry suitable operating mechanism hereinafter described. One end of the casing is provided witha cylindrical tube 2 to which is anchored one end of a hereinafter mentioned strap 3. Mounted between the sides of the casing is a roller 4 which is free to rotate on a pin 5 preferably riveted to the sides of the casing; this roller 4 is positioned between the beforementioned cylindrical tube 2 and a locking arrangement 6 which is mounted and free to rotate on a pin '7 preferably riveted to the sides of the casing the effective face of which locking arrangement is provided with a number of teeth 8, the tops of which are slightly rounded and are for the purpose of gripping the strap 3 passing over the roller 4 and between said roller 4 and locking arrangement 6. The teeth 8 of the locking arrangement 6 are formed on a segment which is adapted to be partly rotated so as to grip the strap 3 and force it against the roller 4 preventing it from slipping past the roller 4 in one direction and allowing it to be pulled through and around the roller 4 in the opposite direction which action lifts the locking arrangement 6 and allows the strap 3 to pass freely. The end of the strap 3 which is anchored to the casing l as beforementioned passes from there through a shackle 9 pivotally attached to a suitable hook 10 from which shackle 9 the strap 3 is returned through the bottom of the casing 1 around the front of the roller 4 between the said roller 4 and toothed segment 6.

The free end of the strap 3 forms the means .11 whereby tension is applied to the wire 11 held between the hereinafter mentioned gripping jaws which tension is prevented when desired from being released by the teeth 8 of the segment 6 gripping the strap 3 on the tendency of the strap 3 being pulled in an opposite direction to that applied to it when placing the wire 11 in tension. Mounted integral with the front of the boxlike casing 1 is one end of an offset connecting arm 12 preferably bowed and of a required length the continuation of the centre line of which preferably passes through the longitudinal centre line of the roller 4 over which roller 4 the free end of the strap 3.passes. Pivotally mounted near the opposite end of the bowed connecting arm 12 is a jaw operating lever 13 of desired length which is pivotally mounted to a plate hereinafter referred to as the lower gripping jaw 14, this jaw operating lever 13 is normally inclined at an angle and has pivotally attached to its upper portion one end of a plate hereinafter referred to as the upper gripping jaw 15, the other end of this upper gripping jaw 15 being connected to the lower gripping jaw 14 by a link 16 which is pivotally attached to both jaws 14 and 15 in such a manner as to allow the upper jaw 15 to move in parallel relationship to the lower jaw 14. Integral with the lower jaw 14 is a downwardly projecting plate 17 of suitable shape the lower end of which is provided with an opening 18 preferably counter 130 sunk on both sides through which opening 18 is free to pass the curved end of the bowed connecting arm 12. This opening 18 acts as a guide to maintain the upper surface of the lower jaw 14 in constant position in relation to the line of di- .135 rection of pull of the apparatus which is a continuation of the line of direction of the wire 11 under strain when said wire 11 is gripped between the upper and lower gripping jaws 15 and 14 respectively.

The gripping jaw 14 is provided with a spring 19 one end of which is fixed to said lower jaw 14 the other end of which spring 19 registers with the jaw operating lever 13 and maintains the upper jaw 15 in closed position upon the lower the opening 18 in the lower portion of the plate 17 integral with the lower gripping jaw 14.

I do not wish to be arbitrarily confined to details since I may if necessary have to depart therefrom, and while I have described the essential characteristics of my invention I desire it to be understood that various improvements and modifications may be embodied without departing from its spirit and scope.

I claim:-

1. An improved grip comprising tension imparting mechanism including a casing, a bowed ofiset arm extending from said casing, a guiding lever and a pivoted operating lever mounted in spaced relationship on the outer end of the bowed arm, spring controlled gripping jaws carried on the spaced levers the effective portion of the gripping jaws being always in alignment with the direction of pull exerted on the tensioning mechanism for the purposes specified.

2. An improved grip having tension imparting mechanism including a casing and flexible anchoring means, an offset bowed arm extending from said casing, a lever pivoted to said bowed arm, spring controlled gripping jaws disposed on the upper end of said lever and above the outer end of the bowed arm and a guiding lever connected with the lower jaw and disposed on the outer end of the bowed arm to operate said jaws to grip a wire or cable.

3. An improved grip having a tension imparting mechanism including a casing and an offset bowed arm extending outwardly from said casing, a curved end on said arm having mounted thereon a pivoted lever and. a guiding lever respectively, said levers converging together to support spring controlled jaws, a pivoted link connected to the adjacent end of each jaw to impart a substantially parallel movement thereto substantially as and for the purposes specified.

4. An improved grip having a tension imparting mechanism including a casing, an offset bowed arm extending from said casing, a pivoted lever and a guiding lever mounted on the outer end of said arm, a slot in the lower end of the: guiding lever to permit of a limited movement through said slot of a curved end on the bowed arm, spring controlled gripping jaws disposed on the upper ends of said levers with the upper jaw pivotally mounted and adapted to be spaced from and in alignment with the tension imparting mechanism, a link disposed in parallel relationship with the pivoted lever and pivoted to each adjacent end of the gripping jaws the ends of which jaws are rounded for the purposes specified.

5. An improved grip comprising tension imparting mechanism including a casing, flexible anchoring means associated therewith, a bowed oifset arm extending from said casing, a lever pivoted to said bowed arm, spring controlled gripping jaws disposed on said lever, a link pivoted to said jaws to maintain same parallel during operation and means for maintaining the lower jaw in fixed relation to the direction of pull exerted on the tensioning mechanism.

BERNARD MCMAHON. 

